In recent years there has been a significant increase in demand for beverages to serve as an alternative to conventional beverages, such as juices and carbonated beverages. More recently, significant interest has arisen for clear and/or colorless beverages. At the same time, there has been a significant interest in beverages which can add health benefits to the consumer beyond re-hydration. In particular, vitamin and/or mineral fortified beverages are of significant interest. One desired vitamin for inclusion in beverages is L-ascorbic acid, or so called vitamin C.
It was proposed by the present inventors to provide clear and/or colorless, and/or light color beverages with vitamin fortification. In particular, it was proposed to include L-ascorbic acid in at least a significant percentage of the U.S. Recommended Daily Requirement of L-ascorbic acid, with other vitamins including B vitamins.
Water solutions of L-ascorbic acid are initially clear and colorless. However, after a period of time, the solutions become discolored and may also become somewhat turbid. It is believed that the discoloration (yellowing or browning) and turbidity occur from reaction products of the L-ascorbic acid according to the following reasons. Small amounts of transition metals, in particular iron, copper, and zinc, present in the water or as impurities in other constituents of a beverage, catalyze oxidation of the L-ascorbic acid. See for example: MingLong Liao & Paul A Seib; Food Chemistry, 30 (1988) 289,312 at 297. Oxidized forms of L-ascorbic acid, commonly referred to as dehydroascorbic acid, are highly susceptible to non-enzymatic browning reactions that lead to a colored (off-color) solution. Certain reaction products can also cloud a clear solution.
It is also known that L-ascorbic acid plays an active role in browning (Maillard) reactions. One of the oxidation products of L-ascorbic acid is threose. It is believed, that threose further reacts with nitrogen-containing constituents which may also be in a beverage, such as Aspartame and certain B vitamins (e.g., Niacin and Pantothenic acid). The resulting Maillard reaction products may also cause an undesirable off color change and/or turbidity.
Certain conventional products which contain L-ascorbic acid are not color and/or clarity stabile. Other products have co-constituents which mask the color and/or clarity change caused by reaction of the L-ascorbic acid. There are those products too, which may use L-ascorbic acid for other than bioavailability and hence may be at sufficiently low concentrations to cause less of a problem with color and/or clarity change.
Color masking, or more particularly, color change masking, may be provided by natural or synthetic constituents which impart a sufficiently strong color to the aqueous solution. Examples of natural constituents which can mask color change due to oxidation of L-ascorbic acid are: carotenoids; tea or tea components; fruit juice concentrates; carmine red, cochineal extract or combinations of these. Examples of synthetic constituents which can mask color change due to oxidation of L-ascorbic acid are: FD&C dyes; caramel colors; or combinations of same.
Turbidity masking, or more particularly turbidity change masking, may be provided by natural or synthetic constituents which impart a sufficiently strong turbidity to the aqueous solution. Examples of constituents which can mask a change in turbidity or clarity due to oxidation of L-ascorbic acid are: natural fruit or vegetable juice solids, tea, cloudifiers; or, combinations of these.
However, a problem is posed for a beverage that would not have constituents strong enough to mask a change in color or turbidity due to oxidation of L-ascorbic acid. A particular problem would be posed for a vitamin C fortified beverage intended to be marketed as clear and colorless. For those consumers seeking such a beverage, any discoloration or turbidity could cause a lack of appeal. A problem would even exist for beverages where some light coloration is either added by design or merely acceptable to consumers. This is because oxidation of L-ascorbic acid takes place over a period of time. Hence, products which are packaged at different times will appear to be different in color and/or clarity. This difference will be more dramatic if the products have different thermal histories during processing and/or storage.
Also, hot filling of a beverage permits reduction or elimination of additives for preventing mold, yeast or other microbes. However, the elevated temperatures experienced during pasteurization are believed to greatly accelerate the oxidation of L-ascorbic acid and hence discolorization. Finally, as noted above, there is a disincentive for adding desirable nutrients such as B vitamins into a proposed color stabile non-masked beverage due to the potential additional discoloration from the Maillard reactions.
U.S. Pat. No. 5,202,141 issued to Mc Evilly, et. al. is directed to the use of at least one substituted resorcinol derivative in combination with an additive to prevent browning in food. Amongst the additives are ascorbic acid and chelating agents including ethylene-diaminetetraacetic acid (EDTA). However, McEvilly discloses no criticality or basis for using the two additives together. To the contrary, McEvilly discloses the use of ascorbic acid as a reducing agent, which is antithetical to preserving the L-ascorbic acid in a state of bio-availability as vitamin C. More importantly, McEvilly discloses that this combination (as well as all other suggested combinations of additives) cannot prevent browning in foods or beverages "that is not initiated by PPO catalysis (nonenzymatic browning)." (McEvilly, Col. 3 Ins. 10-11).
U.S. Pat. No. 5,738,888 issued to Cirigliano et. al. is directed to the use of chelating agents including EDTA to prevent the degradation of Natamycin used as an antimicrobial agent in teas.
U.S. Pat. No. 5,336,510 issued to Chang is directed to use of riboflavin to prevent "decolorization" (bleaching or fading ) of azo dyes in beverage syrup caused by the reduction of the dyes by L-ascorbic acid. The riboflavin is used to transfer hydrogen ions from the L-ascorbic acid to oxygen to leave dehydroascorbic acid. The goal in the transfer is to present a preferential reaction to the reduction of the azo dye by the L-ascorbic acid. However, there appears to be no disclosure of concern for the "discoloration" which may be caused by further reaction of the dehydorascorbic acid. This is presumably because of the masking effect of the dye on such discoloration.
The present invention solves the above discussed and other problems for providing a color and clarity stabile beverage without the use of masking constituents.